/*
 * This file is part of the AzerothCore Project. See AUTHORS file for Copyright information
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef AZEROTHCORE_SESSIONKEYGENERATOR_HPP
#define AZEROTHCORE_SESSIONKEYGENERATOR_HPP

template <typename Hash>
class SessionKeyGenerator
{
public:
    template <typename C>
    SessionKeyGenerator(C const& buf) :
        o0it(o0.begin())
    {
        uint8 const* data = std::data(buf);
        std::size_t const len = std::size(buf);
        std::size_t const halflen = (len / 2);

        o1 = Hash::GetDigestOf(data, halflen);
        o2 = Hash::GetDigestOf(data + halflen, len - halflen);
        o0 = Hash::GetDigestOf(o1, o0, o2);
    }

    void Generate(uint8* buf, uint32 sz)
    {
        for (uint32 i = 0; i < sz; ++i)
        {
            if (o0it == o0.end())
            {
                o0 = Hash::GetDigestOf(o1, o0, o2);
                o0it = o0.begin();
            }

            buf[i] = *(o0it++);
        }
    }

private:
    typename Hash::Digest o0{};
    typename Hash::Digest o1{};
    typename Hash::Digest o2{};
    typename Hash::Digest::const_iterator o0it;
};

#endif
